Switch between edit controls using Tab? - c++

Question

The Window is non DialogBox based so WS_TABSTOP doesn't work. Moreover I don't want to Tab through all the controls, I just want to Tab through few Edit controls.
What I did is I superclassed the Edit control and handled the WM_KEYDOWN message, switching between edit controls, by getting next window in the line thorugh ::GetWindow(hwnd,GW_HWNDNEXT); Also I would like to switch focus back to the first Edit control when I have reached the last one.
The Code doesn't work for when I have reached the last Edit control, the ::GetWindow simply returns the next window in the line(?), which happens to be a non superclassed edit control. And there are more hidden child windows(SW_HIDE).
Maybe if I know how to know the class name of the window's HWND ?
Note: Pure Win32 api, c++ oop.
else if ( ( int ) wParam == VK_TAB )
{
HWND nextInLine;
nextInLine = ::GetWindow ( hwnd, GW_HWNDNEXT );
if ( hwnd == NULL ) nextInLine = ::GetWindow ( hwnd, GW_HWNDPREV );
::SendMessage ( nextInLine, EM_SETSEL, ( WPARAM ) 0, ( LPARAM ) -1 );
::SetFocus ( nextInLine );
return 0;
}

Answer 1

You get keyboard navigation for free in any window by using the IsDialogMessage API call. To consume the service a window message loop has to be modified to include a call to IsDialogMessage and only pass the message on to regular message handling if it hasn't been handled by the dialog manager already.
MSG msg = { 0 };
while (GetMessage(&msg, NULL, 0, 0)) {
if (IsDialogMessage(hwnd, &msg)) {
/* Already handled by dialog manager */
} else {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
Don't forget to set the WS_EX_CONTROLPARENT extended window style on the parent window, so that the dialog manager recurses into child windows.

Answer 2

It's possible to get away with just calling IsDialogMessage, but the result isn't quite 100% dialog-like. To make an ordinary window behave like a dialog:
Specify DLGWINDOWEXTRA as the cbWndExtra field of your WNDCLASS (don't forget to add on extra space you might already be using and offset your data's indexes)
Call DefDlgProc rather than DefWindowProc
Since this makes your window a dialog, you need to use the DWLP_USER window long instead of GWLP_USERDATA, if you're using that, when calling GetWindowLongPtr or SetWindowLongPtr.
(From memory, the main thing you get from doing the above is support for WM_NEXTDLGCTL, which I've found useful to use for supporting changing focus using the Enter key, using Method I described in http://support.microsoft.com/kb/102589.)
Then in your message pump, call IsDialogMessage for each dialog-like window in your message pump.
Finally, when creating controls for your dialog-like window, set the WS_TABSTOP window style for each window you want to participate in the tabbing, and set the WS_EX_CONTROLPARENT window exstyle (aka Control Parent in the resource editor) for child windows that contain dialog controls.